JPH0629084U - Structure of sheet heating element - Google Patents

Abstract

(57) [Summary] [Objective] It is thin, light, can withstand external force, has good thermal energy efficiency, and has uniform temperature distribution characteristics.
The present invention relates to a structure of a planar heating element for the purpose of providing a heater which can freely select the shape of the heating element, has no variation in quality such as electric characteristics and temperature characteristics, and has good productivity and low cost. [Structure] The pattern of the resistor is photoengraved on the electrothermal alloy foil material, and the heat-generating foil resistor is molded by precision etching. This heating foil resistor is stretched on a substrate on which an insulating film is electrically formed by alumina oxidation treatment on the surface of an aluminum plate to form a planar heating element.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This plan is a planar heating element characterized by an arbitrary heating element shape, high density and uniform or arbitrary temperature distribution characteristics, efficient heat conduction, low energy loss, thin and light weight, and rigidity that can resist external stress. It relates to the structure of.

[0002]

[Prior art]

 An electric heating alloy wire rod (generally nickel-chromium wire) is stretched over pottery, ceramic material, heat-resistant glass, etc., or a groove is formed so that the electric heating wire rod can be easily inserted to form a heater. Alternatively, the heater is formed by winding or tensioning a wire rod for electric heating on a mica plate. In particular, for mass production of small and lightweight heaters, there is also a product in which a sheet-like heating element is produced by a technology (thick film technology) in which a paste-like alloy for electric heating is silk-screen printed on a ceramic plate and baked in a baking furnace to form a heater.

[0003]

[Problems to be solved by the device]

 The currently commercialized heaters have the following unavoidable problems due to the material surface of the heating wires and heat insulating materials used and the structural restrictions caused by these materials. 1. The dimensions, especially the thickness, cannot be reduced. 2. The heat-resistant substrate that holds the heating wire is weak against shock, bending, and twisting and easily damaged. If it has sufficient rigidity, the thickness increases and the weight becomes heavy. 3. The temperature distribution does not become uniform, or conversely an arbitrary temperature distribution cannot be obtained. 4. Can't make spot heating or heating element to fit any shape. 5. It is difficult to automate the process of attaching and winding the heating wire. 6. Due to the material and shape of the heat-resistant substrate or insulator, thermal efficiency and heat conduction are poor and energy loss becomes large.

[0004]

[Means for Solving the Problems]

 The heating foil resistor 1 is formed by plate-making a resistor pattern on the alloy foil sheet for electric heating or the alloy foil hoop material for electric heating by photolithography and performing precision etching in an iron chloride-based solution. The shape of the heating foil resistor 1 can freely change the resistor pattern according to the temperature distribution and temperature characteristics required for the sheet heating element, and because of the photoengraving technology, the dimensional accuracy is high and the temperature distribution and individual characteristics are uniform. Can be extremely reduced. The aluminum plate is subjected to electrolytic treatment to form an alumina oxide film on the surface to form a substrate 2 having an electrically insulating film. The substrate 2 holds the heating foil resistor 1 to form a planar heating element. For the purpose of protecting the heat-generating foil resistor 1, if the upper surface of the heat-generating surface is covered with heat-resistant glass, polymide or a heat-resistant resin material such as Teflon, or a mica plate to give a heat insulating effect, only one side of the aluminum substrate surface is covered. It can be a heating element. If the upper surface of the heating surface is covered with the aluminum plate 2 also having an alumina oxide insulating film, the heating foil resistor 1 is built-in to form a planar heating element that generates heat from both surfaces.

[0005]

[Work]

 The patterned heating foil resistor has a small cross-sectional area and can be used as a resistor with a long effective length, and has a large specific resistance.Because the pattern shape is precise, there is no individual difference and there is no variation in electrical resistance. Further, since the gap between the resistors is small, it is possible to construct a packaged heater so as to obtain a high density and uniform temperature distribution. The aluminum substrate has good thermal conductivity, low energy loss, and high efficiency, so it can be used as an electric heater with low power consumption. Since it has rigidity, it can withstand impact, bending, twisting, etc. even if the plate thickness is thin, so that the overall thickness can be made extremely thin, resulting in a lightweight and highly efficient sheet heating element. Furthermore, although some metal resistors are easily oxidized in a heat generation state in the atmosphere and cannot be used for a long time, in the present proposal, nitrogen or argon is used to eliminate oxygen when processed by the aluminum substrate and the cover. By sealing in an inert gas and suppressing the amount of residual oxygen, oxidative corrosion during long-term use can be minimized. Since the heating foil resistor is processed by photolithographic technology and silk screen printing, it can be made into a special shape, a spot, a pinpoint, or a heater shape that is optimal for heating or keeping heat in a limited zone. If an alumina oxide film is formed around the outer wall and bottom of the aluminum inner pot of the electric rice cooker, and a heating foil resistor is placed and the outer periphery is coated with a heat insulating material, a direct heating type rice cooker can be obtained. In the same way, it is possible to transfer the technology to consumer cooking equipment such as boiling type kettles and frying pans.

[0006]

【Example】

 Fig. 1 shows an example in which an alloy foil sheet material for electric heating is processed by photolithography technology and precision etching technology to be molded as a heating foil resistor. FIG. 2 shows a structure of a planar heating element in which a heating foil resistor antibody is sandwiched between two aluminum substrates having an alumina oxide film surface to generate heat from both surfaces. FIG. 3 is a sectional view showing the structure of a direct heating type inner pot of an electric rice cooker. Figure 4

4. An example in which a groove having the same pattern shape as that of the metal foil resistor is formed on the aluminum substrate by etching as described in [4]

[0007]

[Effect of device]

 Compared to other conventional products, it is a planar heating element characterized by extremely small variations in electrical and temperature characteristics, compactness, easy handling, safety, high thermal energy efficiency, and durability that is resistant to damage. It is able to meet the demands of all industries, industrial fields, and consumer fields.

[Brief description of drawings]

FIG. 1 is an example of a pattern of a metal foil resistor for heat generation.

FIG. 2 is an example in which a planar heating element is formed by sandwiching a metallic foil resistor for heating with two aluminum substrates having a surface electrically insulated by an alumina oxide film.

FIG. 3 is a cross-sectional view showing a structure of an inner pot of a direct heating type electric rice cooker in which heat-generating metal foil resistors are attached to the outer periphery and the bottom of the inner pot.

[Fig. 4] To prevent the foil resistor from being affected by external force, the surface of the aluminum substrate is etched into a concave shape in the same shape as the pattern of the heating foil resistor, and a groove is formed to embed the foil resistor. Aluminum substrate (pattern surface is treated with alumina oxide film)

[Explanation of sign]

1 Heat generating foil film resistor 2 Aluminum substrate electrically insulated by alumina oxide film 3 Inner pot of electric rice cooker (outer periphery and bottom surface are treated with alumina oxide film) 4 Inner pot of electric rice cooker Heated foil resistor 5 pasted on 5 Coating material for protection of heat generating foil resistor and heat insulating effect 6 An example in which the aluminum substrate surface is concavely processed into the same shape as the pattern of the heat generating foil resistor is shown.

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[Procedure amendment]

[Submission date] July 29, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

Claims (4)

[Scope of utility model registration request] 1. A heating foil resistor is formed by photolithography a pattern of a resistor on an alloy foil sheet for electrical heating or an alloy foil hoop material for electrical heating and performing a precision etching process. A structure of a sheet heating element, characterized in that the heating foil resistor is attached to an aluminum substrate as an electrical insulating film by forming an alumina oxide film on the surface by electrolytic treatment to constitute an electric heater. 2. A heat-generating foil resistor in which the surface of the heat-generating foil resistor having the structure of claim 1 to which an electric heater is attached is covered with a heat-resistant resin material such as heat-resistant glass, polymide or Teflon, or a mica plate for the purpose of heat insulation. The structure of the sheet heating element that protects the heat generated from the aluminum substrate surface, and the opposite surface is insulated by the heat insulating material. 3. A heat-generating foil resistor having a structure according to claim 1, wherein the surface of the heat-generating foil resistor to which the electric heater is adhered is further covered with an aluminum substrate which is made to have an alumina oxide film and is electrically insulated. Structure of sheet heating element with built-in body electric heater to generate heat from both sides. 4. When the heating foil resistor is pasted with the electric heater having the structure according to any one of claims 1, 2 and 3, after the aluminum substrate surface is etched into a concave shape having the same shape as the pattern of the heating foil resistor. , A structure of a sheet heating element in which an alumina oxide film is generated to serve as an electrical insulator, and a heating foil resistor is incorporated in the concave surface so that the resistor is stable even when a physical force is applied.